Obesity surgery may 'cure' diabetes for 15 years

CHICAGO — Obesity surgery may keep diabetes in remission even after 15 years in some patients, a study suggests.

Long-term results were missing for more than half the patients who began the study and remission rates dropped off considerably. But still, 35 out of 115 patients remained diabetes-free 15 years after surgery. Also, 20 years after surgery, about 25 patients remained free of diabetes complications including eye and kidney problems.

Results were similar for three types of weight-loss surgery: gastric bypass, stomach banding and an operation that involves banding and stapling.

The study of obese diabetics in Sweden began with about 340 who had surgery and 260 treated with medication and lifestyle changes. Results were published Tuesday in the Journal of the American Medical Association.

Previous research has found that weight-loss surgery is more effective than usual diabetes treatment at reversing the disease. The new results suggest the same thing but they aren't conclusive because long-term data was missing for so many patients.

The lead author, Dr. Lars Sjostrom of Sahlgrenska University Hospital in Gothenburg, Sweden, said his research is the longest follow-up to date but that the results need to be confirmed in more rigorous studies.

Patients who had been diagnosed with diabetes for less than one year when the study began had the best long-term results.

Scientists aren't certain how obesity surgery "cures" diabetes. It usually results in much more weight loss than other treatment, which happened in the Swedish patients, and that may improve the body's use of insulin. Also, gastric bypass, the most common obesity surgery in the United States, can alter hormones and other substances produced during digestion, which may reduce diabetes risk.